Topographic Maps. I. Introduction

Transcription

1 Topographic Maps I. Introduction A. Topographic maps are essential tools in geologic and engineering studies because they show the configuration of Earth's surface in remarkable detail and permit one to measure horizontal distances and elevations. This is accomplished by means of carefully surveyed connecting points of to represent elevations of hills and valleys. They are also used by the military, hikers, hunters, campers, and anyone who for whom knowledge of the three-dimensional nature of the land surface is useful. B. Topographic Maps are also called. II. Representing Elevation A. Contour Lines 1. Connect points of with respect to. 2. Represent distance (altitude can also be used). 3. Contour lines are plotted in. 4. Bathymetric contours a. Show the shape and slope of the surface b. Shown in, depending on their location. 5. Index Contours a. brown lines with elevations printed on them. b. Usually every line. c. Not used if the map area has low. (1) Relief is the difference between the and elevation. (2) A region with low relief will be relatively. (3) In areas with low relief, few contour lines will be required and all will be labeled. 6. The Contour Interval a. The difference in elevation between two contour lines. b. Specified on maps as either or. c. Maps use the smallest contour interval that will allow easy readability and provide as much detail as possible. (1) intervals are used if there is a high relief. (2) intervals are used for low relief. 7. Rules for Contour Lines a. Every point on a contour line is of the exact elevation. b. Contour lines always close to form an irregular. (1) Sometimes part of a contour line the mapped area. (2) This is why the entire circle formed can t be seen. ESC 101: Professor Vorwald Topographic Maps Page 1 of 6

2 c. Contour lines cross one another. (1) A map location can t have elevations. (2) A rare exception is where an is present. In this case the hidden contour lines are dashed. (3) If the cliff is vertical the contour lines will merge to form a contour line. d. Gradient (Slope) (1) Gradient is a measure of the of a slope. (2) Gradient is determined by finding the over a distance. Expressed as: (a) Feet per mile (b) Meters per kilometer (for metric maps) (3) Can be inferred by the of the contour lines. (Figure 1) (a) A steeper gradient will be shown by contour lines. (b) The more gentle the gradient, the the contour lines will be spaced. e. Stream Valleys (1) Contour lines form a when crossing a stream. (Figure 2) (2) The apex of the V always points towards the elevation. f. A concentric series of circular close contour lines represents a. (Figure 3) g. Depressions: (1) Depression contour lines have marks on the downhill side. (2) They represent depressions. (3) Contour lines on opposite sides of the depression. (a) This means that the contour line inside the depression has the elevation as the last contour line outside. (Figure 4) (b) If the depression is on a slope, the contour lines will repeat on side. (Figure 5) Figure 1 Figure 2 Figure 3 ESC 101: Professor Vorwald Topographic Maps Page 2 of 6

3 Figure 4 Figure 5 B. Vertical Control Points 1. These are symbols on a map that indicate the at that location. 2. Some types of vertical control points: a. Bench Marks (1) A set into the ground. (2) It s position has been surveyed as accurately as possible. (3) Abbreviated BM. (4) Shown as a with the elevation if latitude and longitude coordinates are certain. (5) If VABM next to a triangle symbol it indicates the elevation was determined by a surveying technique that used a vertical angle (hense, the letters VA). (6) If shown as by an BM X symbol with the elevation. (a) The horizontal position has been surveyed as accurately as possible, but exact coordinates haven t been determined. (b) Instead of a brass plate, the marker is a concrete tablet with the numbers etched onto the top (like a gravestone). b. Recoverable Mark (1) Naturally occurring whose horizontal position has been surveyed as accurately as possible. (2) Shown by an X symbol with the elevation. (3) Referred to as a. III. Latitude and Longitude on Topographic Maps A. Quadrangles 1. Topographic maps are a whose borders are lines of and. 2. Because most maps cover of Earth s surface whole degrees aren t used. a. Maps are published in sizes using and of latitude and longitude. ESC 101: Professor Vorwald Topographic Maps Page 3 of 6

4 b. Two common sizes (1) 7 ½ minute quadrangle (a) Covers (7' 30") of latitude and longitude. (b) Most common map published by the United States Geologic Survey (USGS.) (2) 15 minute quadrangle (a) Covers (15' 00") of latitude and longitude. (b) Covers times the area of a 7 ½ minute quadrangle. (c) This size is no longer published by the USGS 3. The Direction to North a. North is always at the of the quadrangle grid b. Longitude lines (meridians)form the and borders of the map. c. They aren t parallel because meridians toward the north. d. Grid North ( ) (1) At the top of the quadrangle grid. (2) Based on a grid constructed on the map. (3) About the same as true north ( ) on the actual Earth. B. Magnetic North is not the same as True North 1. Magnetic North ( ) a. The direction in which Earth s magnetic lines of force. b. This is in the same location as true north and moves 10 to 40 km per year. c. It s currently about 1,000 km from the true North Pole, in Hudson Bay, Northern Canada (at o o 82.7 N, W in 2005). 2. Magnetic Declination a. The between (MN) and (shown by a star). b. Because magnetic north is continually changing, this is good only for the year of the map. c. IV. Map Scale A. What is meant by scale? 1. Maps are. 2. Scale is the by which the real distance has been reduced. 3. All scales are shown on the bottom of the map. B. Ratio Scale 1. Expresses how much a certain distance on the map equals on the real Earth. 2. Units are in inches (centimeters if the contour lines are in meters). 3. Samples a. 1:24,000 (1) One inch on the map represents in real distance on Earth s surface. (2) Used on 7 ½ minute quadrangle maps ESC 101: Professor Vorwald Topographic Maps Page 4 of 6

5 b. 1:62,000 (1) Once inch on the map represents in real distance on Earth s surface. (2) Used on 15 minute quadrangle maps. c. 1:100,000 (1) One centimeter on the map represents (1 km) in real distance on Earth s surface. (2) Used on metric maps. C. Fractional Scale 1. Indicates that map has been reduced to the. 2. Ratio Scale can easily be expressed as. a. 1:24,000 equals a fractional scale of 1/24,000. b. 1:62,000 equals a fractional scale of 1/62,000. c. 1:100,000 equals a fractional scale of 1/100,000. D. Bar Scale 1. Printed in the lower margin. 2. Four types: a. Miles b. Feet c. Kilometers (subdivided into meters) V. Map Symbols and the Use of Color A. Features and Symbols 1. Shown as points, lines, or areas, depending on their size and extent. 2. Individual houses may be shown as small black squares. For larger buildings, the actual shapes are mapped. 3. In densely built-up areas, most individual buildings are omitted and an area tint is shown. On some maps, post offices, churches, city halls, and other landmark buildings are shown within the tinted area. 4. Various point symbols are used to depict features such as buildings, campgrounds, springs, water tanks, mines, survey control points, and wells. Names of places and features are shown in a color corresponding to the type of feature. Many features are identified by labels, such as "Substation" or "Golf Course. B. : 1. The used colors usually indicate similar classes of information. 2. Colors used: a. : Contour lines b. : Vegetation (e.g., woods, orchards, and vineyards) c. : Water features such as lakes, swamps, rivers, and drainage d. : Classifies cultural features ( man-made ), such as populated areas, main roads, and boundaries e. : Cultural features (e.g., buildings, roads, railroads, mines, towers, etc.) ESC 101: Professor Vorwald Topographic Maps Page 5 of 6

6 f. : At one time, purple was used as a revision color to show all feature changes. Currently, purple is not used in the USGS revision program, but purple features are still present on many existing maps. VI. Public Land Survey System (PLS) Refer to Laboratory Manual VII. Universal Transverse Mercator System (UTM) Refer to Laboratory Manual ESC 101: Professor Vorwald Topographic Maps Page 6 of 6

Topographic Map Symbols From the USGS http://egsc.usgs.gov/isb/pubs/booklets/symbols/ What is a Topographic Map? A map is a representation of the Earth, or part of it. The distinctive characteristic of

TOPOGRAPHIC MAPS MAP 2-D REPRESENTATION OF THE EARTH S SURFACE TOPOGRAPHIC MAP A graphic representation of the 3-D configuration of the earth s surface. This is it shows elevations (third dimension). It

MAP PICTIONARY MAPS Latitude Lines run east west Main latitude line is the equator (0 degrees). Lines are numbered 0 90 degrees, north and south of the equator. Both north and south poles are 90 degrees.

BIOL 2406 Fall 2011 Topographic Maps A topographic map is a two dimensional representation of a three dimensional land surface. Elevation or relief is shown through the use of contour lines that are continuous

Earth Systems Science Laboratory 5 Using and Interpreting Topographic Maps This semester, you will be studying the valley of the Florida River, east of Durango. The Florida River is a source of water for

Topographic Maps Topographic Maps show the topography, or the surface features of the earth. -- Show natural features * ex.: rivers, hills, valleys, etc. -- Show constructed (man-made) features as well

Name: Class: Date: Topographic Maps One of the best ways of studying a land region is with a topographic map. The United States Geological survey prints topographic maps of all parts of the United States.

What is a map? A Map is a two or three-dimensional model or representation of the Earth s surface. 2-Dimensional map Types of Maps: (just a few that we may be using) Political Maps Shows borders of states,

New Page 2 of 3 http://raider.muc.edu/~mcnaugma/topographic%20maps/topomapindex... 2/17/2005 2:03 PM TOPOGRAPHIC MAPS Topographic maps are important tools for studying the earth surface, not only for geologists,

1. Model: A representation of a real object or event. Ex: Map Globe Graphs A. Models are useful because they allow an easier way to study objects or events. 2. The shape of the Earth A. The earth is round.

MAKING A THREE DIMENSIONAL TOPOGRAPHIC MAP A topographic map shows elevation. Each "circle" (these are never perfect circles - usually very squiggly) and sometimes only part of the circle, indicates how

How to Read a Topographic Map by Debra Ronca Howstuffwork.com Topographic maps allow you to see a 3-D landscape on a 2-D surface. How to Read a Topographic Map We're all familiar with maps. They're those

Name School LAB 4: Topographic Maps & Google Earth Our earth is a very complex place to view as a flat map. Viewing the earth, as a globe is the best representation we can have it is both proportionate

Map Reading II 1 Objectives Apply map reading skills using aspects taken from marginal information on a military map Interpret different terrain features based on a map s changing topographic contour intervals

Or, I m lost. How do I find my way back to the trailhead? Read topographic maps Understand geographic coordinate system (Lat, Lon) Plot Lat/Lon coordinates on maps Read Lat/Lon coordinates off maps See

MAPS, MAP READING, AND LAND NAVIGATION LESSON 1: INTRODUCTION TO MAPS PURPOSE Knowing how to read and understand maps are valuable skills that can strengthen your awareness of the world around you. Your

Lesson 4 How to Read a Topographic Map Key teaching points A topographic map is a representation of a three-dimensional surface on a flat piece of paper. The digital elevation model on the poster is helpful

CHAPTER 3 3 Types of Maps SECTION Models of the Earth KEY IDEAS As you read this section, keep these questions in mind: How are elevation and topography shown on a map? What are three types of information

SJSU Geol 4L Planet Earth Lab Lab 5 p. 1 of 8 Lab 5: Topography and Topographic Maps In this lab, you ll learn some of the tools available to help geologists recognize and interpret the topography of Earth

Standard 1.h: Read and interpret topographic and geologic maps. Topographic contours indicating surface relief. Image taken from US Army training manual. In this lesson, you will learn about the ways to

Objective TOUR OF A TOPO Copyright GeoQuest Publications 1 The student will demonstrate how to use the information on a topographic map to 1) determine the name, location, and source of a quadrangle map,

NOTES Topo Maps.notebook symbols to show the surface A map that uses features of an area as if you were looking down on it from above. Otego, NY Apr 12 8:41 AM Unadilla, NY accurate information, such as:

Topographic Maps Practice Questions and Answers Revised October 2007 1. In the illustration shown below what navigational features are represented by A, B, and C? Note that A is a critical city in defining

Maps A Primer for Content & Production of Topographic Base Maps For Design Presented by Definition and Purpose of, Map: a representation of the whole or a part of an area. Maps serve a wide range of purposes.

Three Ways to be 3-D Understanding Topographic Maps Over erview iew These three activities are designed to help students visualize how contour lines on a topographical map relate to three-dimensional landforms.

Using Topographic Maps Procedure This lab has three parts: (1) Making a contour map of Turtle Island, an imaginary island with known spot elevations, (2) constructing a topographic profile across Turtle

aeronautical chart A chart or map used for air navigation, which provides the aircraft pilot with important information about flight paths, airport approaches and facilities, as well as landmark features.

SECTION VII - NAUTICAL CHARTS and CHART NO. 1 INTRODUCTION: In conjunction with the ATON/CU Program, it is necessary for Auxiliary members to understand the general composition and purposes of NAUTICAL

From Topographic Maps to Digital Elevation Models Anne Graham Daniel Sheehan MIT Libraries IAP 2013 Which Way Does the Water Flow? A topographic map shows relief features or surface configuration of an

Maps A map is a representation of the Earth, or part of it. Humans have always needed to find their way from place to place and their most common way of doing this and providing information about their

EASTERN SHORE GROUND SEARCH AND RESCUE Map & Compass Course GSAR EXPECTATION Map and compass skills are not optional for searchers. All searchers MUST be able to use a map and compass easily and effectively.

SCIENCE Lesson 6 A Source of Fresh Water Wilderness Watersheds Objectives: Students will: understand common U.S. Geological Survey map symbols including contour lines. choose a river and trace its tributaries

Lab 1: Getting to Know the Earth s Surface through Maps A big part of geoscience is the presentation of information about the characteristics of the Earth s surface; the elevation, the underlying geologic

COMPOSED AND PRODUCED BY : Chris Rule. Permission is granted for use by acknowledging the author s name. UTM stands for Universal Transverse Mercator which is a technical term for the type of map projection.

Oregon Geographic Information Council (OGIC) GIS Program Leaders Cartographic Elements Best Practices Version 1.0.7 Introduction The purpose of this document is to serve as a set of Oregon best practices

LESSON 14: TOPOGRAPHIC MAPS Key Concepts In this lesson we will focus on summarising what you need to know about: Locating exact position (degrees, minutes and seconds) Relative position, direction and

Map-Reading Lab Geography 1 You will use the Soquel and Mount Whitney USGS Quads for this activity. 1. What are the exact titles of the two maps? &. 2. What is the name of the type of projection used to

TO GO TO ANY OF THE PAGES LISTED BELOW, CLICK ON ITS TITLE CHAPTER 1 The Structure of Earth 1 1-1 What is the study of Earth science? 2 1-2 What are the main parts of Earth? 3 1-3 What is the structure

Map reading made easy What is a map? A map is simply a plan of the ground on paper. The plan is usually drawn as the land would be seen from directly above. A map will normally have the following features:

1.3 Representing Earth s Surface Key Concepts What lines on a globe are used to indicate location? What problems do mapmakers face when making maps? How do topographic maps differ from other maps? Vocabulary

IVL 1 Surveying - Introduction to Topographic Modeling 1/8 Introduction Topography - defined as the shape or configuration or relief or three dimensional quality of a surface Topography maps are very useful

Map and Compass Maps Information from the Field Book for Canadian Scouting A topographic map shows details of a portion of the earth s surface drawn to scale on paper. The features shown fall into four

Name: Answer Key Earth Science Date: Period: ANSWER KEY Page 1 Density Three different bars of soap are being investigated by a group of students. They measured the mass and volume of each bar and recorded

What is GPS? Global Positioning System (GPS) The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere

Basic Map & GPS Skills How to read a topographic map, use a compass, and determine GPS locations on a map Table of Contents This booklet covers what a topographic map (topo map) is, how to use a map, and

Searching Land Records thru the BLM General Land Office Records. Land Records can be an exciting addition to your family history search. The United States Government transferred ownership of land to millions

MiSP Topographic Maps Worksheet #2 Name Date CONSTRUCTING AND STUDYING A CONTOUR MAP Introduction: You previously used the make believe Ellipse Island to study contour maps. That activity had ideal contour

Maps and Map Projections How Maps Can Mislead Us A Globe Is the only truly accurate representation of the earth A flat surface It is easy to portray a flat surface on a flat piece of paper But there is

Grade 6 Book 3 Map Work 1 Map Work I am my best work a series of road maps, reports, recipes, doodles, and prayers... Audre Lord Book 3 - Map Work Grade 6 Term 1 (Social Science - Geography) Looking at

Map Projection, Datum and Plane Coordinate Systems Geodetic Control Network Horizontal Control Network Datum A datum is a set of parameters defining a coordinate system, and a set of control points whose

MiSP Topographic Maps Worksheet #1a Name Date Introduction: SLOPE AND TOPOGRAPHIC CONTOURS Topographic contours are shown by lines of different widths. Each contour is a line of equal elevation; therefore,

Geography 8 th Grade Social Studies The 5 Themes of Geography 1.1 1. Location- Where something is located. Absolute location: the absolute or specific location as in using coordinates of a map with latitude